The present application relates to inverse water-in-oil latices, to their process of preparation and to their application as thickeners and/or emulsifiers for skincare and haircare products and for the manufacture of cosmetic, dermocosmetic, dermopharmaceutical or pharmaceutical preparations.
Synthetic thickening polymers, provided in the form of inverse latices, are disclosed as being able to be used in the manufacture of topical compositions in the French patent applications published under the numbers 2 721 511, 2 733 805, 2 774 688, 2 774 996 and 2 782 086 and in the European patent application published under the number EP 0 503 853.
However, some of them sometimes produce intolerance reactions with some types of sensitive skin.
That is why the Applicant Company has taken an interest in looking for novel polymer emulsions which are better tolerated by the skin than those of the state of the art.
A subject-matter of the invention is a composition comprising an oil phase, an aqueous phase, at least one emulsifying agent of water-in-oil (W/O) type and at least one emulsifying agent of oil-in-water (O/W) type in the form of a self-invertible inverse latex comprising from 20% to 70% by weight and preferably from 25% to 50% by weight of a branched or crosslinked polyelectrolyte, characterized in that the said polyelectrolyte is either a homopolymer based on a monomer having a partially or completely salified strong acid functional group or a copolymer based on at least one monomer having a partially or completely salified strong acid functional group copolymerized with acrylamide and characterized in that the constituent solvent of the oil phase is chosen from white mineral oils, squalane, hydrogenated polyisobutene, isohexadecane or isododecane.
Isohexadecane, which is identified in Chemical Abstracts by the number RN=93685-80-4, is a mixture of C12, C16 and C20 isoparaffins comprising at least 97% of C16 isoparaffins, among which the main constituent is 2,2,4,4,6,8,8-heptamethylnonane (RN=4390-04-9). It is sold in France by Bayer.
Isododecane is sold in France by Bayer.
Hydrogenated polyisobutene is sold in France by Ets B. Rossow et Cie under the name Parleam-Polysynlane(trademark). It is mentioned in: Michel and Irene Ash; Thesaurus of Chemical Products, Chemical Publishing Co. Inc., 1986, Volume I, page 211 (ISBN 0 7131 3603 0).
Squalane is sold in France by Sophim under the name Phytosqualan(trademark). It is identified in Chemical Abstracts by the number RN=111-01-3. It is a mixture of hydrocarbons comprising more than 80% by weight of 2,6,10,15,19,23-hexamethyltetracosane.
The term xe2x80x9cwhite mineral oilxe2x80x9d is understood to mean, in the context of the present invention, a white mineral oil in accordance with the FDA regulations 21 CFR 172.878 and FR 178.3620(a).
A more particular subject-matter of the invention is a composition as defined above in which the constituent white mineral oil of the oil phase is Marcol(trademark)52. Marcol(trademark)52 is a commercial oil corresponding to the definition of liquid paraffins of the French Pharmacopoeia.
According to a second specific aspect of the present invention, the constituent solvent of the oil phase of the inverse latex is hydrogenated polyisobutene.
According to a third specific aspect of the present invention, the constituent solvent of the oil phase of the inverse latex is squalane.
According to a fourth specific aspect of the present invention, the constituent solvent of the oil phase of the inverse latex is isohexadecane.
According to a fifth specific aspect of the present invention, the constituent solvent of the oil phase of the inverse latex is isododecane.
The term xe2x80x9cbranched polymerxe2x80x9d denotes a nonlinear polymer which has pendant chains, so as to obtain a high state of entanglement when this polymer is dissolved in water, resulting in very high viscosities at a low gradient.
The term xe2x80x9ccrosslinked polymerxe2x80x9d denotes a non-linear polymer which exists in the state of a three-dimensional network which is insoluble in water but swellable in water and which thus results in the production of a chemical gel.
The composition according to the invention can comprise crosslinked units and/or branched units.
The term xe2x80x9cemulsifying agent of the water-in-oil typexe2x80x9d denotes emulsifying agents having an HLB value which is sufficiently low to provide water-in-oil emulsions, such as the surface-active polymers sold under the name of Hypermer(trademark) or such as sorbitan esters, for example the sorbitan monooleate sold by Seppic under the tradename of Montane 80(trademark) or the sorbitan isostearate sold by Seppic under the tradename of Montane 70(trademark). These emulsifying agents can also include the sorbitan oleate ethoxylated with 5 mol of ethylene oxide sold by Seppic under the tradename of Montanox(trademark) 81.
The term xe2x80x9cemulsifying agent of the oil-in-water typexe2x80x9d denotes emulsifying agents having an HLB value which is sufficiently high to provide oil-in-water emulsions, such as ethoxylated sorbitan esters, for example the sorbitan oleate ethoxylated with 20 mol of ethylene oxide sold by Seppic under the name of Montanox(trademark)80, the ethoxylated castor oil comprising 40 mol of ethylene oxide sold by Seppic under the name of Simulsol(trademark) OL 50, the ethoxylated sorbitan laurate comprising 20 mol of ethylene oxide sold by Seppic under the name of Moneanox(trademark)20 or the ethoxylated lauryl alcohol comprising 7 mol of ethylene oxide sold by Seppic under the name of Simulsol(trademark) P7.
Emulsifying agents having an HLB value which is sufficiently high to provide oil-in-water emulsions also include the compounds of formula (I):
R1xe2x80x94Oxe2x80x94[CH(R2)xe2x80x94CH2xe2x80x94O]nxe2x80x94(G)xxe2x80x94Hxe2x80x83xe2x80x83(I), 
in which R1 represents a saturated or unsaturated and linear or branched hydrocarbonaceous radical comprising from 1 to 30 carbon atoms, R2 represents a hydrogen atom or an alkyl radical comprising 1 or 2 carbon atoms, G represents the residue of a saccharide, x represents a decimal number between 1 and 5 and n is equal either to zero or to an integer between 1 and 30.
The term xe2x80x9cresidue of a saccharidexe2x80x9d denotes, for G, a bivalent radical resulting from the removal on a sugar molecule, on the one hand, of a hydrogen atom of a hydroxyl group and, on the other hand, of the anomeric hydroxyl group. The term xe2x80x9csaccharidexe2x80x9d denotes in particular glucose or dextrose, fructose, mannose, galactose, altrose, idose, arabinose, xylose, ribose, gulose, lyxose, maltose, maltotriose, lactose, cellobiose, dextran, talose, allose, raffinose, laevoglucan, cellulose or starch. The oligomeric structure (G) can exist under any form of isomerism, whether optical isomerism, geometrical isomerism or positional isomerism. It can also represent a mixture of isomers.
In the formula (I) as defined above, the radical:
R1xe2x80x94Oxe2x80x94[CH(R2)xe2x80x94CH2xe2x80x94O]nxe2x80x94
is bonded to G via the anomeric carbon, so as to form an acetal functional group. The divalent group xe2x80x94[CH(R2)xe2x80x94CH2xe2x80x94O]nxe2x80x94 represents either a chain composed solely of ethoxyl groups (R2xe2x95x90H) or a chain composed solely of propoxyl groups (R2xe2x95x90CH3) or a chain composed both of ethoxyl groups and of propoxyl groups. In the latter case, the fragments xe2x80x94CH2xe2x80x94CH2xe2x80x94Oxe2x80x94 and xe2x80x94CH(CH2)xe2x80x94CH2xe2x80x94Oxe2x80x94 are distributed in the said chain in a block or random fashion.
The number x, which represents, in the formula (I), the mean degree of polymerization of the saccharide, is more particularly between 1 and 3, in particular between 1.05 and 2.5, very particularly between 1.1 and 2.0 and preferably less than or equal to 1.5.
Emulsifying surface-active agents having an HLB value which is sufficiently high to provide oil-in-water emulsions include more particularly the compounds of formula (I) as defined above in which G represents the glucose residue or the xylose residue and/or in which n is equal to 0 and/or in which R1 represents a radical comprising from 8 to 18 carbon atoms and more particularly in which R1 represents a radical chosen from the octyl, decyl, undecyl, dodecyl, tetradecyl or hexadecyl radicals, the said radicals being linear or branched.
Commercial products comprising the said compounds include, for example:
Simulsol(trademark)SL8, sold by Seppic, which is an aqueous solution comprising between approximately 35% and 45% by weight of a mixture of alkyl polyglycosides consisting of between 45% by weight and 55% by weight of a compound of formula (I) in which G represents the glucose residue, x is equal to about 1.45, n is equal to 0 and R1 represents a decyl radical and between 45% by weight and 55% by weight of a compound of formula (I) in which G represents the glucose residue, x is equal to approximately 1.45, n is equal to 0 and R1 represents an octyl radical;
Simulsol(trademark) SL10, sold by Seppic, which is an aqueous solution comprising between approximately 40% by weight and 50% by weight of a mixture of alkyl polyglycosides consisting of approximately 85% by weight of a compound of formula (I) in which G represents the glucose residue, x is equal to approximately 1.45, n is equal to 0 and R1 represents a decyl radical, approximately 7.5% by weight of a compound of formula (I) in which G represents the glucose residue, x is equal to approximately 1.45, n is equal to 0 and R1 represents a dodecyl radical and approximately 7.5% by weight of a compound of formula (I) in which G represents the glucose residue, the number x is equal to approximately 1.45, n is equal to 0 and R1 represents a tetradecyl radical;
Simulsol(trademark) SL11, sold by Seppic, which is an aqueous solution comprising between approximately 40% by weight and 50% by weight of a mixture of alkyl polyglycosides consisting of approximately 85% by weight of formula (I) in which G represents the glucose residue, x is equal to approximately 1.45, n is equal to 0 and R1 represents an undecyl radical; or
Simulsol(trademark) SL26, sold by Seppic, which is an aqueous solution comprising between approximately 40% by weight and 55% by weight of a mixture of alkyl polyglycosides consisting of approximately 70% by weight of a compound of formula (I) in which G represents the glucose residue, x is equal to approximately 1.45, n is equal to 0 and R1 represents a dodecyl radical, approximately 25% by weight of a compound of formula (I), in which G represents the glucose residue, x is equal to approximately 1.45, n is equal to 0 and R1 represents a tetradecyl radical and approximately 5% by weight of a compound of formula (I) in which G represents the glucose residue, x is equal to approximately 1.45, n is equal to 0 and R1 represents a hexadecyl radical.
The strong acid functional group of the monomer comprising it is in particular the sulphonic acid functional group or the phosphonic acid functional group, partially or completely salified. The said monomer can be, for example, partially or completely salified styrenesulphonic acid. It is preferably 2-methyl-2-[(1-oxo-2-propenyl)amino]-1-propanesulphonic acid, partially or completely salified in the form of an alkali metal salt, such as, for example, the sodium salt or the potassium salt, of the ammonium salt or of a salt of an aminoalcohol, such as, for example, the monoethanolamine salt.
According to a sixth specific aspect of the present invention, the polyelectrolyte included in the inverse latex as defined above is a copolymer comprising, in molar proportions, from 30% to 50% of 2-methyl-2-[(1-oxo-2-propenyl)amino]-1-propanesulphonic acid (AMPS(trademark)), salified in the form of the sodium salt or of the ammonium salt, and from 50% to 70% of acrylamide.
According to a seventh specific aspect of the present invention, the polyelectrolyte included in the inverse latex as defined above is a homopolymer of 2-methyl-2-[(1-oxo-2-propenyl)amino]-1-propanesulphonic acid salified in the form of the sodium salt or of the ammonium salt.
A subject-matter of the invention is, more particularly, a composition as defined above, characterized in that the polyelectrolyte is crosslinked and/or branched with a diethylenic or polyethylenic compound in the molar proportion, expressed with respect to the monomers employed, of 0.005% to 1%, more particularly of 0.01% to 0.5% and very particularly of 0.1% to 0.25%. The crosslinking agent and/or the branching agent is chosen from diallyloxyacetic acid or one of its salts, such as sodium diallyloxyacetate, ethylene glycol dimethacrylate, ethylene glycol diacrylate, diallylurea, trimethylolpropane triacrylate, methylenebis(acrylamide), triallylamine or a mixture of these compounds.
According to an eighth specific aspect of the present invention, the polyelectrolyte included in the inverse latex as defined above is crosslinked with triallylamine.
The inverse latex as defined above generally comprises from 4% to 10% by weight of emulsifying agents. Generally, from 20% to 50% and more particularly from 25% to 40% of the total weight of the emulsifiers are of the water-in-oil type and from 80% to 50% and more particularly from 75 to 60% are of the oil-in-water type.
Its oil phase represents from 15% to 40% and preferably from 20% to 25% of its total weight. This latex can additionally comprise one or more additives chosen in particular from complexing agents, transfer agents or chain-limiting agents.
A subject-matter of the invention is also a cosmetic, dermocosmetic, dermopharmaceutical or pharmaceutical composition, characterized in that it comprises as thickening compound, at least one inverse latex as defined above.
The cosmetic, dermocosmetic, dermopharmaceutical or pharmaceutical composition defined above generally comprises from 0.1% to 10% and more particularly between 0.5% and 5% by weight of the said inverse latex. It is provided in particular in the form of a milk, of a lotion, of a gel, of a cream, of a soap, of a foam bath, of a balm, of a shampoo or of a conditioner.
Generally, the said inverse latex can advantageously replace the products sold under the name Sepigel(trademark) 305 or Sepigel(trademark) 501 by the Applicant Company in cosmetic, dermopharmaceutical or pharmaceutical compositions as it also exhibits good compatibility with the other excipients used in the preparation of formations such as milks, lotions, creams, soaps, foam baths, balms, shampoos or conditioners. It can also be used in combination with the said Sepigel products. It is in particular compatible with the concentrates disclosed and claimed in international publications WO 92/06778, WO 95/04592, WO 95/13863, WO 98/47610 or FR 2734 496 or with the surface-active agents disclosed in WO 93/08204.
It is particularly compatible with Montanov(trademark) 68, Montanov(trademark) 82, Montanov(trademark) 202, Montanov(trademark) WO18, Montanov(trademark) S or Sepiperl(trademark) N. It can also be used in emulsions of the type of those disclosed in EP 0 629 396 and in cosmetically or physiologically acceptable aqueous dispersions with an organopolysiloxane compound chosen, for example, from those disclosed in WO 93/05762 or in WO 93/21316. It can also be used to form cosmetically or physiologically acceptable aqueous gels with an acidic pH, such as those disclosed in WO 93/97856; it can also be used in combination with nonionic celluloses to form, for example, styling gels, such as those disclosed in EP 0 684 024, or in combination with esters of fatty acids and of sugar to form compositions for the treatment of the hair or of the skin, such as those disclosed in EP 0 603 019, or in shampoos or conditioners, such as disclosed and claimed in WO 92/21316, or finally in combination with an anionic homopolymer, such as Carbopol(trademark), to form hair treatment products, such as those disclosed in DE 195 23596. It is also compatible with numerous active principles, such as, for example, self-tanning agents, such as dihydroxyacetone (DHA), or antiacne agents; it can thus be introduced into self-tanning compositions, such as those claimed in EP 0 715 845, EP 0 604 249 or EP 0 576 188 or in WO 93/07902. It is also compatible with N-acylated derivatives of amino acids, which allows it to be used in soothing compositions, in particular for sensitive skin, such as those disclosed or claimed in WO 92/21318, WO 94/27561 or WO 98/09611. It is also compatible with glycolic acids, with lactic acid, with salicylic acid, retinoids, phenoxyethanol, sugars, glyceraldehyde, xanthans, fruit acids and the various polyols used in the manufacture of cosmetic formulations.
Another subject-matter of the invention is thus the use of an inverse latex as defined above in preparing a cosmetic, dermocosmetic, dermopharmaceutical or pharmaceutical composition.
The examples which follow have the aim of illustrating the present invention without, however, limiting it. They show that the novel inverse latices do not irritate the skin and that their physical properties allow them to be used in the preparation of cosmetic, dermopharmaceutical or pharmaceutical compositions intended more particularly for the treatment of sensitive skin.
A) Examples of preparations of compositions according to the invention